The present invention relates to a filter attachment of a filter cigarette manufacturing system, and more specifically, to a predrying apparatus provided in the filter attachment for moderately drying paste applied to a tip paper.
A filter attachment of a filter cigarette manufacturing system comprises a wrapping section for winding a piece of tip paper on a joining portion between a cigarette rod and a filter plug. For the supply of tip paper pieces to the wrapping section, the filter attachment comprises a paste applicator section for applying paste to one surface of a tip paper and a cutter section for cutting the pasted tip paper into tip paper pieces. The paste may overreach tip paper piece as the tip paper piece is wrapped, owing to an excessive moisture content of the paste applied to the tip paper or other reasons, to lower the external appearance quality of the filter cigarette. In order to eliminate such trouble and improve the initial adhesion of the paste, a predrying apparatus for drying the tip paper or the paste applied thereto is provided between the paste applicator section and the cutter section.
For example, a predrying apparatus is known, which is designed to heat an unpasted tip paper in advance by means of a heater that is embedded in a tip paper transfer roller. With this apparatus adapted to heat the tip paper before the application of paste, it is difficult to adjust the degree of dryness of the paste applied to the tip paper. Thus, the paste can be predried unsatisfactorily, so that it may overreach the tip paper piece. Conversely, the paste can be excessively dried, thereby lowering its adhesion to cause air leakage or warping of the tip paper piece.
Thus, there have been proposed apparatuses for predrying a tip paper- or paste thereon after the tip paper is applied with the paste. For example, these apparatuses include one which is of a type adapted to heat a tip paper by bringing a heater block in contact with a non-paste side surface of the tip paper or adapted to dry paste by directly blowing warm air onto a paste-side surface of a tip paper.
However, in the case of a predrying apparatus using a heater block to heat a non-paste side surface of the tip paper, it is still hard to appropriately adjust the degree of dryness of the paste on the tip paper. Since the tip paper applied with the hydrous paste is lowered in fiber strength, if an undesired force act between the heater block and the tip paper in contact therewith, the tip paper may be deformed. If the tip paper is deformed, a tip paper piece cannot be satisfactorily wound on a joining portion between a cigarette rod and a filter plug, and hence the external appearance of a cigarette may be ruined. Furthermore, in order to operate a cigarette manufacturing machine at high speed to increase the cigarette manufacturing speed, it is necessary to increase the tip paper transfer speed in the predrying apparatus. However, the frequency of occurrence of deformation of the tip paper, attributable to the contact between the tip paper and the heater block in the predrying process, generally increases as the tip paper transfer speed increases. It is difficult, therefore, to operate the predrying apparatus provided with a heater block at high speed to fit the high-speed operation of the cigarette manufacturing machine.
In the case of the predrying apparatus adapted to blow warm air, there is a small possibility of the blown warm air producing a force to deform the tip paper since the air serving as a heat transfer medium is highly compressible. In other words, there is a low possibility of the tip paper being deformed as it is predried. Since the warm air is blown on the paste side surface, the degree of dryness of the paste on the tip paper can be adjusted more satisfactorily than in the case where the non-paste side surface is heated. On the other hand, the predrying apparatus of this type typically comprises a hood located right over paper guides which define a tip-paper transfer face and a blower connected through a blower hose to an air inlet port in the hood. This predrying apparatus is designed to supply electric power to a heating wire mounted as a heat source in the hood, thereby heating air fed from the blower. The resulting warm air is blown from a lower opening of the hood onto the paste-side surface of the tip paper transferred along the paper guides. This predrying apparatus has a complicated construction as explained above and requires a wide installation space. Moreover, the warm air blown off from the hood may thermally influence the component parts of the filter attachment and the cigarette manufacturing machine that are arranged around the predrying apparatus. Isolating these peripheral component parts from the warm air requires large-scale incidental equipment and constitutes a hindrance to the simplification or compactification of the construction of the predrying apparatus.
An object of the present invention is to provide a tip paper predrying apparatus capable of predrying paste applied to a tip paper without deforming the tip paper and of being constructed relatively easily and compactly.
In order to achieve the object, according to the present invention, there is provided a tip paper predrying apparatus for use in a filter attachment that includes a paste applicator section for applying paste to one surface of an elongate tip paper delivered from a roll, a cutter section for cutting the pasted tip paper into tip paper pieces, and a wrapping section for wrapping a tip paper piece around a joining portion between a cigarette rod and a filter plug.
The tip paper predrying apparatus of the present invention comprises a transfer section having a transfer path extending between the paste applicator section and the cutter section, and a heat radiation section including at least one heat radiator, disposed opposite the transfer path at a distance from the tip paper transferred along the transfer path from the paste applicator section, for radiating heat rays toward a paste-side surface of the transferred tip paper.
According to the predrying apparatus of the present invention, the paste-side surface or pasted surface of the tip paper is irradiated with heat rays while the pasted tip paper is transferred from the paste applicator section to the cutter section. The paste on the tip paper is heated to be predried by means of the heat rays. In a conventional predrying apparatus using a heater block as a heat source, the tip paper must be brought into contact with the heat source in order to conduct heat from the heat source directly to the tip paper. According to the present invention, the paste applied to the tip paper can be predried in a condition that the heat radiator serving as a heat source is out of contact with the tip paper. Therefore, even a tip paper of which the fiber strength is lowered by the application of the paste can be predried, without any possibility or with a substantially lowered possibility of the tip paper being deformed. Thus, according to this invention, there is no contact or friction between the tip paper and the heat source, so that the tip paper may be predried without being deformed even if the tip paper transfer speed is increased. Thus, the predrying apparatus of this invention is conducive to a speed-up of the operation of filter attachments that is required for a high-speed operation of cigarette manufacturing machines. As compared with the conventional predrying apparatus using warm air, the apparatus of this invention has a simpler construction and requires no wide installation space. In the case where warm air is used, the warm air may exert thermal influences upon peripheral elements. In order to eliminate or reduce the thermal influences, the peripheral elements must be isolated from air flows serving as heat transfer medium. Since the direction of propagation of the air flows changes freely, isolating the air flows from the peripheral elements requires large-scale incidental equipment. According to this invention in which the heat rays that propagate rectilinearly are employed instead of air flows, the heat rays can be intercepted on this side of the peripheral elements as required, whereby the thermal influences of the heat rays upon the peripheral elements can be removed with ease.
Preferably, in the present invention, the at least one heat radiator of the heat radiation section extends across the transfer path and radiates heat rays to the paste-side surface of the transferred tip paper throughout the width region of the paste-side surface.
According to this preferred mode, the entire paste-side surface of the tip paper can be heated, so that the paste on the tip paper can be predried satisfactorily.
Preferably, the heat radiation section includes a plurality of heat radiators arranged along the transfer path.
With this preferred mode, the tip paper can be moderately predried with use of a required number of heat radiators in consideration of the heat radiation doses of the individual heat radiators and the dose of heat rays absorbed by the paste (especially, moisture content in the paste) applied to the tip paper. Since the heat radiation section is composed of a plurality of heat radiators, the necessary heat-radiation capability of each individual heat radiator can be lowered, whereby the heat radiators can be miniaturized. Thus, the heat radiation section can be made compact as a whole.
Preferably, the heat radiator is an infrared radiator for radiating infrared rays.
More preferably, the infrared radiator includes a lamp housing and at least one infrared lamp attached thereto. The lamp housing has an infrared-ray transmitting surface, such as a glass surface or open surface, opposed to the paste-side surface of the transferred tip paper. The infrared lamp irradiates infrared rays through the infrared-ray transmitting surface of the lamp housing.
According to these preferred modes, the paste applied to the tip paper, especially, moisture content in the paste, can be satisfactorily heated by means of the infrared rays emitted from the infrared radiator, whereby the paste on the tip paper can be predried properly.
Preferably, the tip paper predrying apparatus of this invention further comprises a thermal insulating section including at least one insulating board for intercepting the heat rays from the heat radiator.
With this preferred mode, thermal influences of the heat rays from the heat radiator upon the component parts of the filter attachment and a cigarette manufacturing machine that are arranged around the predrying apparatus can be eliminated by intercepting the heat rays by means of the insulating board, a simple structure.
Further preferably, the thermal insulating section includes a first insulating board, located on the side opposite from the heat radiation section with respect to the transferred tip paper and opposed to the heat radiation section, and second and third insulating boards located on the upstream and downstream sides, respectively, of the heat radiation section in the tip-paper transfer direction. The second and third insulating boards are formed with slits through which the transferred tip paper is passed.
With this preferred mode, the heat radiation section is surrounded by the insulating boards and isolated from the peripheral elements. The heat rays from the heat radiation section are intercepted on this side of the peripheral elements, so that they never exert any thermal influences upon the peripheral elements.
Preferably, in the present invention, at least one of the heat radiation section and the transfer section is relatively movable toward and away from the other section, and the predrying apparatus further comprises an actuator for moving the at least one section toward and away from the other section.
With this preferred mode, the heat radiation section can be relatively moved toward and away from the paste-side surface of the tip paper, and the degree of heating of the tip paper by means of the heat rays can be adjusted by making this relative movement.
More preferably, the predrying apparatus further comprises a controller for controlling the drive of the actuator in accordance with the operating state of the predrying apparatus.
According to this preferred mode, the predrying by means of the heat rays can be made efficiently by, e.g., bringing the paste-side surface of the tip paper and the heat radiation section close to each other when the predrying apparatus is operating. When the predrying apparatus is nonoperating, on the other hand, the paste-side surface of the tip paper and the heat radiation section can be separated from each other, so that scorching of the tip paper and undesired contact between the tip paper and the heat radiation section may be prevented securely.
Alternatively, the predrying apparatus comprises a controller for controlling the drive of the heat radiator in accordance with the operating state of the predrying apparatus.
With this preferred mode, for example, the heat radiator is actuated for heat radiation to make the predrying executable when the predrying apparatus is operating. When the predrying apparatus is nonoperating, on the other hand, the heat-radiating operation of the heat radiator is prohibited to render the predrying inexecutable.
Preferably, the predrying apparatus comprises a detector, located on the downstream side of the heat radiation section in the tip-paper transfer direction, for outputting a detection signal indicative of the predried degree of the paste on the predried tip paper, and a controller for controlling the drive of at least one of the actuator and the heat radiator in accordance with the detection signal.
According to this preferred mode, the distance of separation between the paste-side surface of the tip paper and the heat radiation section and hence the degree of heat radiation from the heat radiator can be adjusted in accordance with the detected degree of dryness of the paste on the predried tip paper, whereby a proper predrying can be achieved.